The present invention relates to a new and improved construction of a solar collector of the type comprising liquid-containing elements and a reflector.
The heretofore known solar collectors can be generally divided into two different types, namely flat collectors and so-called focusing collectors. In the case of the flat collectors, a container through which there is guided a liquid is covered with a radiation-absorbing surface, predominantly a black surface, and which surface upon being irradiated by solar energy heats-up and transfers its heat to the liquid. The heated-up liquid either is transmitted directly to the point of consumption or delivered to a storage tank or other suitable storage. In order to reduce the heat losses of the collector the latter is provided at its rear surface with an insulating layer, and in order to decrease convective cooling the front surface is covered with a glass plate or a plastic plate. The radiation losses from the cover plate are reduced by means of a special coating which readily adsorbs the radiation in the spectrum of sunlight, but hardly radiates energy in the thermal band.
In contrast to a flat collector, in the case of a focusing collector, the incident solar radiation is concentrated at a small area before being absorbed. Therefore, for the same performance there is required a much smaller area, also resulting in lower heat losses and rendering possible correspondingly higher temperatures (see the publication "Solar Energy and Building" by S.V. Szokolay).
Solar collectors are usually situated on the roofs of buildings or other structures. Since a roof only has a limited area which can be used for placement of the solar collectors, difficulties arise with regard to the capacity of the solar collectors.
It has already been proposed to incorporate solar collectors into sunblinds, so that, apart from shielding the interior from solar irradiation, it is possible at the same time to employ the radiation for heating the liquid in the collectors (see part 3 of the above-cited publication).
Yet, with this arrangement difficulties arise inasfar as the state-of-the-art solar collectors are relatively heavy and cannot be collapsed or folded.